The present invention is with respect to an apparatus for dewatering and plastifying mixtures, that have been wetted with water, for the manufacture of explosives, as for example ballistic charges or propellents, using a screw extruder having one or more screws with kneading and conveying elements and a housing, that may be made up of axial sections, and with a filling port for the water containing, that is to say wet, mixture to be used for the manufacture of explosives.